When a military operation is carried out in an urban environment, or in an ambush situation, RPGs (rocket propelled grenades) can be fired from very close range. This means that there is very little travel time between the position of the RPG to the targeted personnel, and thus very little time for the targeted personnel to locate, respond to, and destroy the threat. An explosive countermunition can be used to rapidly engage the incoming threat; however, explosives significantly increase the risk of fratricide. Several active protection systems are in various stages of development and fielding. These include DROZD and ARENA from Russia, Trophy from Israel, Diehl's AWiSS from Germany and NTAPS, SLID from the US as well as US Army Stryker®, which is a light armoured vehicle. These systems have different characteristics, benefits, and drawbacks. DROZD is an explosive close-in countermeasure system firing from fixed tubes and offering limited coverage. ARENA is another close-in system also firing from fixed positions, with better coverage than DROZD but posing a high integration burden due to system size. Trophy is small, fast, has gimbals, and offers wide coverage, but is not multi-shot capable and its explosive may pose problems for a light skinned vehicle. Diehl's system uses a fragmenting grenade with a fairly inflexible timing scheme. NTAPS uses a tracking radar, gimbaled launcher, and rocket countermeasure with a total time line too slow for close-in RPG threats.
US Army Stryker® is a light armoured vehicle with a multi-weapons system including a missile mounted atop its roof. Due to the ample weight and the high inertia of the missile, the base-plate on top of which the missile is mounted has a relatively slow rotational speed. A slow rotational speed is acceptable in this case, as the US Army Stryker® is primarily usable in military operations carried out in open environments, and mainly for threats that are fired from far ranges.
U.S. Pat. No. 7,185,575 describes a system for remote tracking of a tactical missile assembly orientation during targeting and leading to launch from a platform, including a weapon station frame rotatably attached to the platform and a command launch unit attached to the weapon station frame. This system is suitable for heavy military vehicles, such as tanks, since it is very heavy and the missile assembly is an offensive system designed to attack targets such as enemy tanks.
U.S. Pat. No. 7,202,809 proposes to overcome the deficiencies of the dynamic protection systems for heavy military vehicles, designed to primarily counteract missile threats. The '809 patent describes a fast-acting dynamic protection system for light military vehicles defeating RPG (rocket propelled grenade) threats fired from close range. The system minimizes the hazard to troops and civilians nearby. The system uses a plurality of passive sensors to locate the threat and initialize the system. The countermunition used may be one of several choices, with the requisites being that the countermunition provides fast response with low inertia, and is able to damage or destroy the detected threat. A multi-barrel recoilless gun is the weapon of choice. A launching device is used to deploy and aim the countermunition and the tracking means. On board software and electronics are used to control the system.